Systems and methods are provided for detecting flow in a mass flow controller (MFC). The position of a gate in the MFC is sensed or otherwise determined to monitor flow through the MFC and to immediately or nearly immediately detect a flow failure. In one embodiment of the present invention, a novel MFC is provided. The MFC includes an orifice, a mass flow control gate, an actuator and a gate position sensor. The actuator moves the control gate to control flow through the orifice. The gate position sensor determines the gate position and/or gate movement to monitor flow and immediately or nearly immediately detect a flow failure. According to one embodiment of the present invention, the gate position sensor includes a transmitter for transmitting a signal and a receiver for receiving the signal such that the receiver provides an indication of the position of the gate based on the signal received. Other embodiments of the gate position sensor are described herein, as well as systems and methods that incorporate the novel MFC within a semiconductor manufacturing process.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for moving the gate to control flow through the orifice; and a gate position sensor for determining a gate position.
2. The mass flow controller of claim 1 , wherein the actuator oscillates the gate between a closed position and an open position to control flow through the orifice.
3. The mass flow controller of claim 1 , wherein the gate position sensor includes a transmitter for transmitting a signal, and a receiver for receiving the signal, the receiver providing an indication of a gate position based on a received signal.
4. The mass flow controller of claim 1 , wherein the gate position sensor includes a device for applying an electrical potential across the orifice and the gate, and a current detector for detecting current flow through a junction formed by the orifice and the gate when the gate is closed.
5. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for moving the gate to control flow through the orifice; and a gate position sensor for determining a gate position, wherein the gate position sensor includes a physical wave generator for generating a physical signal and at least one physical wave receiver for receiving the physical signal positioned such that the physical wave receiver detects the physical signal propagating from the generator through a junction formed by the orifice and the gate when the gate is closed.
6. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for moving the gate to control flow through the orifice; and a gate position sensor for determining a gate position, wherein the gate position sensor includes a light source and a light detector positioned with respect to the light source and the orifice such that an oscillation of the gate between an opened position and a closed position interrupts a light signal from being received by the light detector.
7. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for moving the gate to control flow through the orifice; and a gate position sensor for determining a gate position, wherein the gate position sensor includes an induction coil and an electromagnetic pulse detector, and wherein movement of the gate generates a magnetically induced signal in the induction coil detectable by the electromagnetic pulse detector.
8. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for oscillating the gate between an opened position and a closed position to control flow through the orifice; a transmitter for transmitting a signal; and a receiver for receiving the signal such that the receiver provides an indication of whether the gate is opened or closed based on the signal received.
9. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for oscillating the gate between an opened position and a closed position to control flow through the orifice; a device for applying an electrical potential across the orifice and the gate; and a current detector for detecting current flow through a junction formed by the orifice and the gate when the gate is closed.
10. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for oscillating the gate between an opened position and a closed position to control flow through the orifice; a physical wave generator for generating a physical signal; and at least one physical wave receiver for receiving the physical signal wherein the physical signal reflects whether the gate is in the opened position or the closed position.
11. The mass flow controller of claim 10 , wherein the physical wave receiver directly detects an increased amplitude in the physical signal transmitted through a junction formed by the orifice and the gate when the gate is closed.
12. The mass flow controller of claim 10 , wherein the physical wave receiver detects a complex wave formed from a superposition of a first physical signal propagated through a structure when the gate is open and a second physical signal directly propagated from the physical wave generator to the physical wave receiver through a junction formed by the orifice and the gate when the gate is closed.
13. The mass flow controller of claim 10 , wherein the physical wave generator and the physical wave receiver include piezoelectric crystals.
14. The mass flow controller of claim 10 , wherein the physical wave generator is the gate such that closing the gate generates a physical wave detectable by the physical wave receiver.
15. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for oscillating the gate between opened and closed positions to control flow through the orifice; a light source positioned on a first side of the orifice; and a light detector positioned on a second side of the orifice such that movement of the gate interrupts the light signal from being received by the light detector.
16. A mass flow controller, comprising: an orifice; a mass flow control gate for controlling flow through the orifice; an actuator for oscillating the gate between opened and closed positions to control flow through the orifice; a magnet; a cooperating induction coil operably positioned with respect to the magnet, wherein the magnet and the induction coil are operably positioned with respect to the gate; and an electromagnetic pulse detector such that movement of the gate generates a magnetically induced signal in the induction coil that is detected by the detector.
17. The mass flow controller of claim 16 , wherein the magnet is selected from the group consisting of: a permanent magnet, and an electrically activated magnetic coil.
18. A gate position sensor, comprising: a transmitter for transmitting a signal in a mass flow controller, wherein a position of a gate in the flow controller affects the signal; and a receiver for receiving the signal, wherein the receiver provides an indication of a gate position within the mass flow controller based on the signal received.
19. An ultrasonic mass flow controller, including: an orifice with an oscillating gate to open and close the orifice to meter semiconductor process gas flow, the oscillating gate having an oscillating period and an adjustable duty cycle to adjust the gas flow; and a gate position sensor operably connected to the oscillating gate to determine a position of the oscillating gate for use in verifying operation of the oscillating gate.
20. The ultrasonic mass flow controller of claim 19 , wherein the gate position sensor includes means to generate and detect current flow through a junction formed by the orifice and the oscillating gate when the oscillating gate is closed.
21. The ultrasonic mass flow controller of claim 19 , wherein the gate position sensor includes means to generate and detect physical waves propagated through a junction formed by the orifice and the oscillating gate when the oscillating gate is closed.
22. An ultrasonic mass flow controller, including: an orifice with an oscillating gate to open and close the orifice to meter semiconductor process gas flow, the oscillating gate having an oscillating period and an adjustable duty cycle to adjust the gas flow; and a gate position sensor operably positioned proximate to the oscillating gate to determine a position of the oscillating gate for use in verifying operation of the oscillating gate.
23. The ultrasonic mass flow controller of claim 22 , wherein the gate position sensor includes means to direct a light through the orifice and means to detect when the oscillating gate blocks the light through the orifice.
24. An ultrasonic mass flow controller, including: an orifice with an oscillating gate to open and close the orifice to meter semiconductor process gas flow, the oscillating gate having an oscillating period and an adjustable duty cycle to adjust the gas flow; and a gate position sensor operably positioned to detect motion of the oscillating gate for use in verifying operation of the oscillating gate.
25. The ultrasonic mass flow controller of claim 24 , wherein the gate position sensor includes means to detect a magnetically induced signal attributable to the motion of the oscillating gate.
26. A mass flow controller, comprising: an orifice; an oscillating gate to open and close the orifice for use in metering semiconductor process gas flow; and means to verify operation of the oscillating gate.
27. The mass flow controller of claim 26 , wherein the gate has an adjustable duty cycle to adjust gas flow through the orifice, and the means to verify operation of the oscillating gate includes means to verify that the oscillating gate is operating with a desired duty cycle.
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August 30, 2001
September 30, 2003
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